The disclosures of Japanese Patent Application Nos. HEI 10-253120 filed on Sep. 7, 1998, HEI 10-253122 filed on Sep. 7, 1998, HEI 10-263623 filed on Sep. 17, 1998 and HEI 10-265514 filed on Sep. 18, 1998 including the specification, drawings and abstract are incorporated herein by reference in their entirety.
1. Field of the Invention
The present invention relates to a vehicle drive device provided with at least a motor as the source of driving force for a running vehicle.
2. Description of the Related Art
Recently, there has been an increasing demand for improving the fuel consumption of a motor vehicle and reducing exhaust gas for environmental protection and effective use of resources. To meet the demand, a conventional internal combustion engine is replaced by or used together with a motor. That is, the former corresponds to an electric automobile and the latter corresponds to a hybrid vehicle. An example of the latter is described in Japanese Patent Application Laid-open No. HEI 08-168104.
The device described in HEI 08-168104 is a hybrid drive device having a motor at an engine output side, a torque converter and a transmission mechanism arranged in this order following the motor. This reference is intended to cancel the pulsation of the engine torque by means of the output torque of the motor. With the above structure in which the motor is associated with the engine and the torque converter, it is possible to regenerate and store energy during deceleration and to start or accelerate the vehicle using the electric power. This improves the fuel consumption and reduces exhaust gas emission.
The above device is achieved by adding a motor to a motor vehicle with an automatic transmission gear using an internal engine as a power source. However, motor vehicles have been subjected to downsizing, reduced weight, and increased cabin space. To meet the aforementioned demands, the capacity of the space accommodating the power unit and its attached equipment is considerably limited. Therefore, if the motor is added and installed linearly between the engine and torque converter as stated above, the overall axial length of the drive device or the size of the drive device is increased, thus deteriorating mountability.
In addition, if a motor is arranged adjacent to the torque converter, the torque converter acts as a coupling means for coupling a power source and a transmission such that the motor is coupled to the torque converter. In this case, the torque converter is expanded and contracted in accordance with a variation in the pressure of internal oil (fluid), which requires a structure for allowing the deformation of the torque converter. Also, the motor is required to accurately set and maintain a gap between a stator and a rotor. As the requirements for mechanisms of the torque converter and the motor are contradicting, it is quite a new technical challenge to provide a small, lightweight vehicle as a whole while satisfying such demands. There has been no conventional techniques to address the aforementioned challenge. Installation of the rotor of the motor generator to the front cover of the torque converter has been proposed for reducing the dimension in the axial direction. In such a case, the front cover may expand or contract resulting from variation of pressure applied to the fluid within the torque converter. As a result, the axial position of the rotor of the motor generator installed to the front cover displaces. This may shift the relative position of the thus displaced rotor with respect to the stator of the motor generator fixed to the transmission cover, thus deteriorating output characteristics. Furthermore, if means such as bolts and splines are employed as means for coupling the torque converter and the motor, there is a possibility of deteriorating the productivity of the overall device by increasing the number of mechanically processed parts and the number of assembly steps.
Moreover, if the fluctuation of the torque output from the engine is suppressed by the output torque of the motor, the output side member of the motor is coupled to the output axis of the engine or the output member thereof. The coupled portion of the means for coupling the engine to the motor and torque converter at the output side of the engine is covered with, for example, a casing. A spline axially slid and engaged is, therefore, normally employed.
In the device above, if the engine output side member is coupled to the motor side member by a spline, the rotor, which is a member at the engine output side, has a large angular moment of inertia. Further, due to the presence of a slight gap of the spline in rotational direction, the fluctuation (or pulsation) of the output torque of the engine causes the engine output side member and the rotor to repeated rotate relatively to each other by the small gap. As a result, the spline teeth repeatedly collide with one another in a rotational direction, thereby possibly causing abnormal sound or noise.
Under these circumstances, the present invention has been made. It is an object of the present invention to provide a vehicle drive device constituted and arranged to meet the mechanical demands while realizing overall downsizing of a hydraulic transmission and a motor.
To attain the above object, a first embodiment of the present invention provides a vehicle drive device comprising a motor including a rotating shaft, a hydraulic transmission provided adjacent the motor in a direction of a rotational center axis and having a shell housing a fluid, a first rotating member extending axially in one direction to said shell, integrally coupled to the shell and a rotating member of the motor and rotatably supported by a bearing member while a movement of the first rotating member to the axial direction is being stopped, and a second rotating member extending to the shell in the axial direction and in a direction opposite to a direction of the first rotating member, integrally coupled to the shell and rotatably supported by a bearing member while an axial movement of the second rotating member is being stopped.
According to the first embodiment, one of the rotating members, integral with the shell of the hydraulic transmission, and the rotating member of the motor are coupled to each other, whereas the other rotating member is rotatably supported by the bearing while the axial movement of the rotating member is stopped. Therefore, the rotating member of the motor is also prevented from moving in the axial direction. This results in the axial position of the rotor that rotates with the rotating member of the motor being fixed. As the axial movement of the rotor of the motor is arrested in the above way, the relative position between the rotor and stator of the motor can be accurately maintained compared with the conventional art in which the rotor of the motor is installed to the outer shell of the fluid gearing.On the other hand, the other rotating member integral with the shell of the hydraulic transmission is rotatably supported by another bearing while axial movement of the other rotating member is allowed. Therefore, if the shell of the hydraulic transmission is deformed due to the fluctuation of the pressure of the internal fluid, the rotating member supported by the other bearing moves axially. Thus, no excessive stress is generated due to the change of pressure. Also, the change of pressure is absorbed by the axial movement of the other rotating member, so that accuracy for supporting the hydraulic transmission and accuracy for the relative positions of the stator and the rotor of the motor can be maintained in a favorable state.
Next, a second embodiment of the present invention provides a vehicle drive device comprising a first housing having an inner peripheral surface, a barrier plate portion protruding radially inward from said inner peripheral surface of said first housing, a second housing to which said first housing is attached, a motor having a stator fixed onto an inner peripheral surface of said first housing and a rotor relatively rotating with said stator, a functional device fixed to said second housing, a hydraulic transmission provided inside of the second housing and adjacent the motor in a direction of a rotational center axis and having a shell housing a fluid, a first rotating member extending axially in one direction to said shell, integrally coupled to said shell and said rotating member of said motor and rotatably supported by a bearing member fixed at inner peripheral side of the barrier plate portion while an axial movement of said first rotating member is prohibited and a second rotating member extending axially to said shell and in a direction opposite to the one direction of said first rotating member, integrally coupled to said shell and rotatably supported by the function device while an axial movement of said second rotating member is allowed.
A third embodiment of the present invention provides a vehicle drive device including a first housing, a barrier plate portion protruding radially inward on an inner peripheral surface of the first housing, a second housing to which the first housing is attached, a functional device fixed to the second housing, a motor having a stator fixed onto an inner peripheral surface of the first housing and a rotor relatively rotating with the stator, and shaft members integral with the rotor and rotatably supported by a bearing member attached to an inner peripheral portion of the barrier plate portion and by the functional device.
According to the third embodiment, the shaft members integral with the rotor are supported by the barrier plate portion integral with the first housing to which the stator is attached. In addition, part of the other shaft member is rotatably supported by the functional device substantially integral with the second housing to which the first housing is attached. The rotor is not supported by the outer shell of the fluid gearing but supported rotatively by the first housing side. Therefore, the member that supports the rotor and the member that attaches the stator are integrated as a whole. As a result, the accuracy of maintaining the relative position between the stator and the rotor can be increased compared with the conventional art in which the rotor is installed to the outer shell of the fluid gearing.
A fourth embodiment of the present invention provides a vehicle drive device including a first source of driving force that generates power, a motor arranged, together with the first source of driving force, on a rotational center axis and including a stator arranged to be radially distant from the rotational center axis and a rotor relatively rotating with the stator, and a hydraulic transmission having a small diameter portion deformed to have a smaller outer diameter than an inner diameter of the stator, arranged so that the small diameter portion is inserted into an inner peripheral side of the stator and inputting power from the first source of driving force.
In the fourth embodiment, the hydraulic transmission may include an input side member, output side member, and a clutch radially arranged inside the small diameter portion and directly coupling the input side member and the output side member.
According to the fourth embodiment, the motor and the hydraulic transmission, which are connected in series in terms of power transmission, are arranged to radially overlap each other. That is, part of the hydraulic transmission intrudes into the axial space occupied by the motor. Due to this, the axial space can be effectively used and the axial length can be reduced.
A fifth embodiment of the present invention provides a vehicle drive device having a first source of driving force that generates power through an output member, a hydraulic transmission into which power is transmitted from the first source of driving force, a motor arranged between the first source of driving force and the hydraulic transmission and including a stator arranged to be radially distant outside of a rotational center axis and a rotor relatively rotating with the stator, and a damper coupled to the output member of the first source of driving force, arranged at an inner peripheral side of the stator and damping the power transmitted from the first source of driving force. According to the fourth embodiment, the damper coupling the first source of driving force and the hydraulic transmission are arranged to intrude into the axial space occupied by the motor, which is arranged between the first source of driving force and the hydraulic transmission. This makes it possible to effectively use the axial space and to reduce the axial length.
A sixth embodiment of the present invention provides a vehicle drive device including a first source of driving force that generates power, and has an output member, The accuracy of maintaining the relative position between the stator and the rotor can be increased compared with the conventional art in which the rotor is installed to the outer shell of the fluid gearing. A hydraulic transmission into which power is transmitted from the first source of driving force, a motor arranged between the first source of driving force and the hydraulic transmission and comprising a stator arranged to be radially distant from the rotational center axis and a rotor relatively rotating with the stator, a detector arranged at an inner peripheral side of the stator and detecting relative positions of the stator and the rotor in a rotation direction. According to this embodiment, even if the motor is of a type controlled by the relative positions of the stator and the rotor of the motor, the detector, which detects the relative positions of the stator and the rotor, is arranged at the same axial position as that of the motor. Thus, the axial space can be effectively used and the axial length can be reduced.
Furthermore, a barrier plate portion, arranged between the stator and the rotor and the member arranged at a side the first source of driving force may be provided. By doing so, the motor can be arranged in the space determined by the barrier plate portion, thereby maintaining the motor in a fluid-tight state and enhancing sealing property.
More desirably, the detector may include a detector stator and a detector rotor arranged between the stator and rotor of the motor and the first source of driving force and further may include a barrier plate portion arranged between the detector stator and the detector rotor, and the stator and the rotor of the motor. In addition, the detector stator may be attached onto a side surface of the barrier plate portion facing the first source of driving force, and the detector rotor and the rotor of the motor may be attached to a rotating shaft passing through the barrier plate portion. This makes it possible to reduce the axial length. Besides, the detector is attached to the side surface opposite the motor side, i.e., the surface oriented outside of the barrier plate portion among the side surfaces of the barrier plate portion. Due to this, before the first source of driving force is coupled, it is possible to operate the detector from outside, thereby facilitating fine adjustments of the relative positions of the detector stator and the detector rotor of the detector.
A seventh embodiment of the present invention provides a vehicle drive device including a first source of driving force that generates power, a hydraulic transmission into which the power is transmitted from the first source of driving force, an input shaft coupled to the hydraulic transmission and arranged along a rotational center axis of the hydraulic transmission, a motor arranged between the first source of driving force and the hydraulic transmission and including a stator arranged to be radially distant from the rotational center axis and a rotor attached to a portion radially protruding from the input shaft, a barrier plate portion extending radially to the first source of driving force in a direction of the rotational center axis with respect to the motor and including a through hole passing through the input shaft, a detector detecting relative rotations of the stator and the rotor in a rotation direction and including a detector rotor attached to the radially protruding portion of the input shaft at an inner peripheral side of the rotor of the motor and a detector stator fixed onto an inner wall surface of the barrier plate portion and facing the detector rotor radially.
An eighth embodiment of the present invention provides a vehicle drive device including a first source of driving force that generates power, a second source of driving force that has a rotatinal member, a rotating input member having a hub portion provided with a radially protruding plate-shape portion and rotating if the power is transmitted from the first source of driving force to the input member, a hydraulic transmission, into which the power is input from the first source of driving force, including a shell housing a fluid, in which part of the shell of the hydraulic transmission is formed by a front cover having an opening portion formed at a rotational center side, the front cover being integrally fixed to the hub portion and the hub portion forming the part of the shell by fitting the plate-shape portion of the hub portion into the opening portion of the front cover, and the rotational member of the second source of driving force is integrally attached to a portion of the hub portion, the portion being positioned outside of the shell.
Further, the rotating input member may include an input shaft coupled to the output member of the first source of driving force and the hub portion may be formed integrally at an end portion of the input shaft at the hydraulic transmission side. According to this embodiment, the input member serves as a member transmitting power from the first source of driving force to the hydraulic transmission and as a member coupling the second source of driving force and the hydraulic transmission, and the hub portion thereof forms part of the shell of the hydraulic transmission. Due to this, a small space suffices for the coupling portion of these members and the number of parts decreases. As a result, the axial length of the device is shortened as a whole. Additionally, it is possible to employ fixing means, such as welding, as means for integrating the hub portion and the front cover, thereby ensuring the sealing property of the hydraulic transmission. Further, it is possible to integrally form the hub portion of the input means, the front cover and the rotational member of the second source of driving force, thereby not only improving production workability but also reducing assembly man-hours and therefore realizing high productivity.
A ninth embodiment of the present invention provides a vehicle drive device including a first source of driving force that generates power and has a output member, a second source of driving force that has a rotational member, a damper mechanism attached to the output member of the first source of driving force, and a hydraulic transmission having an input side member coupled through a spline to an output side member of the damper mechanism, an rotatinal member of the second source of driving force being coupled to the input side member.
According to the ninth embodiment, the power transmitted from the first source of driving force is transmitted to the damper mechanism, from which the power is transmitted to the hydraulic transmission. At the same time, even if the torque transmitted from the first source of driving force is fluctuated or pulsated, the fluctuation or pulsation is suppressed or leveled by the damper mechanism. Thus, even when the damper mechanism and the input side member of the hydraulic transmission are coupled by a spline and the angular moment of inertia of the rotational member of the second source of driving force acts on the input side member, it is possible to suppress or prevent the occurrence of abnormal sound or noise to the spline portion.
A tenth embodiment of the present invention provides a vehicle drive device including a first source of driving force that generates power and has an output member, a second source of driving force that has a rotational member, a flywheel attached to the output member of the first source of driving force and suppressing a fluctuation of torque output from the first source of driving force, a damper mechanism attached to the flywheel, and a hydraulic transmission having an input side member coupled through a spline to an output side member of the damper mechanism and coupled to the rotational member of the second source of driving force.
With this configuration, the flywheel is rotated by the power transmitted from the first source of driving force and the power is transmitted from this flywheel to the input side member of the hydraulic transmission through the damper mechanism. At the same time, power is transmitted from the input side member to the rotational member of the second source of driving force. In other words, the angular moment of inertia of the rotational member of the second source of driving force acts on the output side member of the damper mechanism. Thus, the fluctuation of torque output from the first source of driving force is suppressed by the flywheel, which has a large angular moment of inertia (or the degree of torque fluctuation is reduced by the damper mechanism). In short, the fluctuation of torque is leveled. Owing to this, even if the input side member of the hydraulic transmission is coupled to the output side member of the damper mechanism by a spline, it is possible to prevent or suppress the teeth of the spline from repeatedly colliding with one another and abnormal sound or noise from occurring following the collision.
The motor does not limit a device which have only a function of a motor. There are various types of motors, for example, a motor which has only a function of a generator, or a motor which has a function of both a motor and a generator.